Photoflash lamp

ABSTRACT

A mechanically ignitable photoflash lamp in which an igniter tube containing a percussive type igniting material is sealed into the lamp bulb. The bulb has a filling of combustible material and a combustion supporting material. To prevent displacement of the combustible material due to the resulting pressure wave, when the igniting material is ignited, the combustible material is a physically stable web, mesh or network of foil or wire designed as a hollow body fitting the shape of the bulb and bearing against the bulb wall.

0 United States Patent 1191 1111 3,734,e7a Liepert 1 May 22, 1973 s41PHOTOFLASH LAMP 2,238,780 4/1941 Reiter ..431 95 2,611,255 9/1952 Poelmaet al ..43l/95 [751 wemngen 3,586,471 6/1971 McDonough ..431/93 many[73] Assignee: Patent-Treuhand Gesellschait fur PrimaryExaminercal'l'oll y, JR

elektrische Gluhlampen mbH, Mu- Attorney- Robert D. Flynn. Stephen H.Frishauf and nich, Germany Leonard Holtz [22] Filed: June 15, 1971ABSTRACT [21] Appl' 153312 A mechanically ignitable photoflash lamp inwhich an igniter tube containing a percussive type igniting [30] ForeignApplication Priority Data material is sealed into the lamp bulb. Thebulb has a July 10 1970 Germany ..P 20 34 328.6 fining of mbustiblematerial and a combustion porting material. To prevent displacement ofthe com- 52 us. c1 ..431/93 hushhle material due to the "Suiting F wave,51 1111. C1 ..F2lk 5 02 when the igniting material is ignited, thecombustible [58] Field of Search ..431/93, 94, 9s material is a P y yStable web, mesh or network of foil or wire designed as a hollow bodyfitting the shape [56] R fere Cit d of the bulb and bearing against thebulb wall.

UNITED STATES PATENTS 3 Claims, 4 Drawing Figures 2,057,583 10/1936 Mey..43l/95 I: Q Q. a

PATENTEU 3 3 I I I INVI'LN'I'OP Reinhold Liepert PHOTOFLASH LAMP CROSSREFERENCE TO RELATED APPLICATION:

U.S. Ser. No. 838,758 filed July 3, 1969 and now US. Pat. No. 3,624,824.

The present invention relates to mechanically ignitable photoflash lampsas disclosed, for example, in application U.S. Ser. 838,758. Suchphotoflash lamps have a metallic igniter tube sealed into the lampenvelope, which is in communication with the interior of the envelope.The end of the tube projects externally of the envelope and is closedand contains a percussionsensitive igniting material. When imparting ablow with a percussive tool on the igniter tube in place which is filledwith igniting material, the igniting material reacts and the flamegenerated thereby and accompanied by a pressure wave, initiates theprocess of combustion in the lamp. The light-generating combustiblematerial in the lamp envelope consists preferably of finely dividedzirconium, and the gaseous atmosphere is oxygen.

The pressure wave generated by ignition of the igniting material maycause an irregular distribution of the combustible material within thelamp envelope; in particular, it may be propelled into the dome of thebulb. This results in irregular light distribution and reduced lightoutput during flashing of the lamp.

It is an object of the invention to provide a lamp in which thedetrimental influence of the pressure wave can be avoided. Subjectmatter of the invention:

The combustible material is designed as a physically stable web ornetwork which has the shape of a hollow body with at least one aperture;it is fitted to the shape of the lamp envelope and is located adjacentto, preferably bearing against the wall of the lamp envelope.

The invention will be explained in greater detail by means of thedrawings.

FIG. 1 shows a lamp in accordance with the invention comprising aphysically stable web or network of combustible material in the shape ofa hollow cylinder open at both ends.

FIG. 2 shows a lamp in accordance with the invention comprising aphysically stable web or network of combustible material in the shape ofa hollow cylinder open at one end.

FIGS. 3 and 4, respectively, show a photoflash lamp according to FIGS. 1and 2, respectively, comprising an igniter tube provided with anignition capsule.

The photoflash lamp comprises a light-transmissive tubular envelope 1,which is filled with combustible material and oxygen at a pressure ofabout 7 at. An igniter tube 3 of copper or of an iron-nickel alloy issealed into one end of the envelope, the igniter tube being incommunication with the interior of the envelope and closed at its end 4projecting externally of the envelope. The portion of the igniter tube 3projecting externally of the envelope is filled with apercussionsensitive igniting material 5. The igniting material may beloosely filled into the igniter tube (FIGS. 1 and 2). Preferably, theigniting material is contained in a capsule 6 (FIGS. 3, 4) provided withan anvil and disposed within the igniter tube.

The end 4 of the igniter tube 3 may be closed by coldpress welding evenafter the igniter tube 3 has been sealed into the glass envelope. It ispreferred, however, to seal an already closed copper tube into the bulb.

The other end of the lamp envelope comprises an exhaust tip 7, which isformed by drawing the lamp envelope off the exhaust tube.

The combustible material in the lamp envelope consists of a physicallystable, that is, form-stable, web, mesh or network of foil or wire,preferably of crimped zirconium shreds, and has the shape of a hollowbody 2 fitted to the shape of the lamp envelope. It has an aperturefacing the igniter tube 3. With a substantially cylindrical envelopeshape, the hollow body 2 has the shape of a hollow cylinder. It may beopen at both ends (FIGS. 1 and 3) or open at one end only (FIGS. 2 and4). The walls of the cylinder are located adjacent the wall of theenvelope. They preferably bear against the walls of the envelope over atleast a major portion thereof. In a lamp of approximately sphericalshape, the shape of the hollow body resembles a hollow sphere providedwith an aperture in a place facing the igniter tube.

By forming the combustible material to the shape of a hollow bodybearing against the wall of the lamp envelope and with an aperturefacing the end of the igniter tube projecting into the lamp envelope,the pressure wave generated by the ignition can freely expand throughthe aperture into the hollow space devoid of igniting material withoutcausing displacement of the combustible material during ignition.

I claim:

1. Photoflash lamp comprising a light-transmitting envelope,

combustible material and a combustion-supporting material located in theenvelope, an igniter tube sealed into the envelope having one end incommunication with the interior of the envelope and the other endprojecting externally of the envelope, the other end being closed andcontaining a percussion-sensitive igniting material,

wherein the combustible material is a physically stable web or networkin the shape of a substantially cylindrical hollow body provided with atleast one axial aperture facing the one end of the igniter tube, the webor network forming said body being shaped to fit the shape of the lampenvelope and located adjacent the wall of the lamp envelope, so that apressure wave generated by ignition of said percussion-sensitiveigniting material can freely expand through said aperture into thehollow space within the hollow body and devoid of igniting material, andwithout causing displacement of the combustible material duringignition.

2. Photoflash lamp as set forth in claim 1, wherein at least a majorportion of the web or network of combustible material bears against amajor portion of the lamp envelope.

3. Photoflash lamp as set forth in claim 1, wherein the physicallystable web or network comprises crimped zirconium shreds.

* a; t a:

1. Photoflash lamp comprising a light-transmitting envelope, combustiblematerial and a combustion-supporting material located in the envelope,an igniter tube sealed into the envelope having one end in communicationwith the interior of the envelope and the other end projectingexternally of the envelope, the other end being closed and containing apercussion-sensitive igniting material, wherein the combustible materialis a physically stable web or network in the shape of a substantiallycylindrical hollow body provided with at least one axial aperture facingthe one end of the igniter tube, the web or network forming said bodybeing shaped to fit the shape of the lamp envelope and located adjacentthe wall of the lamp envelope, so that a pressure wave generated byignition of said percussion-sensitive igniting material can freelyexpand through said aperture into the hollow space within the hollowbody and devoid of igniting material, and without causing displacementof the combustible material during ignition.
 2. Photoflash lamp as setforth in claim 1, wherein at least a major portion of the web or networkof combustible material bears against a major portion of the lampenvelope.
 3. Photoflash lamp as set forth in claim 1, wherein thephysically stable web or network comprises crimped zirconium shreds.